Answer
f(g(x))=x
g(f(x))=x
They are inverses of each other.
Work Step by Step
f(g(x))=3($\frac{x-8}{3}$)+8
f(g(x))=x-8+8
f(g(x))=x
g(f(x))=$\frac{(3x+8)-8}{3}$
g(f(x))=$\frac{3x}{3}$
g(f(x))=x
They are inverses of each other because f(g(x)) and g(f(x)) are both equal to x.